Thomforde, GTI head of cultivation, gave The Republican a tour of the 45,000-square-foot operation that will occupy part of a former paper mill at Appleton and Canal streets.

On opening day the facility will employ 20 to 30 people with 100 to be hired over the next three years. Jobs will be full time with entry-level salaries of $14 an hour with benefits and room for advancement, GTI officials have said.

The exact day operations will begin has yet to be determined, Thomforde said.

"It depends on the construction. We are shooting for the middle of February. It is an old building and there is still time for us to encounter the unexpected. This process has not been a sprint," he said, noting a year of planning and design has preceded the current stage.

Construction Management Builders of Danvers is the general contractor, Thomforde said.

The red-brick building at Appleton and Canal streets was built around 1890, according to the Board of Assessors.

GTI will be renting space in the building that also houses C&D Electronics. The building is owned by W.B.C. Realty Trust, which is headed by Mark Cutting.

GTI CEO Peter Kadens said at a job fair here Nov. 6. that jobs will be as growers, horticulturalists, manual labor, processing the plant once it is harvested, placing it in extraction machines to turn the plant into gases and liquids, chemists, laboratory technicians, management, security, construction and engineering, drying, trimming, curing and processing the plants, crop maintenance and packaging.

The facility will produce 150 pounds to 200 pounds per week of marijuana for shipment to dispensaries like GTI's in Amherst, Thomforde said.

Marijuana's medical uses are available in smoking, edible, drinkable, throat lozenge, skin patch and suppository forms, all of which GTI will produce here, Kadens said.

The facility will have about 40 rooms. Most of the space will be devoted to stocking, growing, trimming, processing, drying and packaging the medical marijuana products. Other spaces will be for employee break rooms and showers, offices, a reception lobby and meeting area, Thomforde said.

Black piping has been installed throughout the facility to drain the 2,000 gallons of water it will use per day, he said.

About 90 percent of the wooden flooring has been replaced, much of it with concrete, which will be free of the power to absorb water that wood is guilty of. Three to four trucks at a time were shooting concrete through tubes into the building for installation as flooring, Thomforde said.

Fixtures will be installed that can expose the marijuana plants to 18 hours of light a day, he said.

"So like we're simulating a perfect day for that plant for its whole life," he said.

Record-keeping at the facility will include attachment of plastic tag with a bar code to every marijuana plant to track the work stations through which each plant was processed, he said.

Rotted lengths of ceiling where leaks have occurred have been removed and replaced with new wooden planks. In one spot, tree-trunk-sized wooden ceiling braces were replaced with an iron beam for added stability, he said.

Bars of solid copper have been installed to conduct electricity because they do so with more capacity than wires, he said.

Metal framing separates areas that with erection of walls and doors will become the nine main work rooms. These are the rooms where the marijuana plants will be stocked, propagated, allowed to flower, trimmed, dried and cured, processed, packaged and finally shipped out by an elevator at the building's Canal Street side, he said.

The marijuana plant's flower is the part that's probably familiar to most people, he said.

"It's like the green stuff that was what we rolled into joints when we were younger. It's like a rose bush. The rose bush has stems and other parts and then at one point of the year, they produce flowers," he said.

A water storage unit with several days of capacity as a back-up will be built in the basement. That's within sight of where old mill machinery like electrical conductors that remind of Dr. Frankenstein's laboratory remain standing.

City departments and the community in general have welcomed GTI, Thomforde said.

"It has been a great experience to be a part of this revitalization effort. It is really a team project," he said.

Such medical marijuana facilities are required to be nonprofit in terms of registering with the state, which means the building and land are not subject to taxation but the equipment in such a facility can be taxed.

The company would pay $50,000 to $100,000 a year into the city general fund and issue $15,000 in grants to community groups as part of a host-city agreement negotiated with Mayor Alex B. Morse.